Up to now the MAPD's ITT size field has been ignored. It encodes
the number of eventid bit minus 1. It should be used to check
the eventid when a MAPTI command is issued on a device. Let's
store the number of eventid bits in the its_device and do the
check on MAPTI. Also make sure the ITT size field does
not exceed the GITS_TYPER IDBITS field.

Signed-off-by: Eric Auger <[email protected]>

---

v3 -> v4:
- VITS_TYPER_IDBITS set to 16 to be homogeneous with VITS_ESZ definition
  and correct users
- nb_eventid_bits correspond to the actual number of eventid bits
---
 include/linux/irqchip/arm-gic-v3.h |  2 ++
 virt/kvm/arm/vgic/vgic-its.c       | 14 +++++++++++++-
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/include/linux/irqchip/arm-gic-v3.h 
b/include/linux/irqchip/arm-gic-v3.h
index d86f963..dcbb3e0 100644
--- a/include/linux/irqchip/arm-gic-v3.h
+++ b/include/linux/irqchip/arm-gic-v3.h
@@ -338,9 +338,11 @@
 #define E_ITS_INT_UNMAPPED_INTERRUPT           0x010307
 #define E_ITS_CLEAR_UNMAPPED_INTERRUPT         0x010507
 #define E_ITS_MAPD_DEVICE_OOR                  0x010801
+#define E_ITS_MAPD_ITTSIZE_OOR                 0x010802
 #define E_ITS_MAPC_PROCNUM_OOR                 0x010902
 #define E_ITS_MAPC_COLLECTION_OOR              0x010903
 #define E_ITS_MAPTI_UNMAPPED_DEVICE            0x010a04
+#define E_ITS_MAPTI_ID_OOR                     0x010a05
 #define E_ITS_MAPTI_PHYSICALID_OOR             0x010a06
 #define E_ITS_INV_UNMAPPED_INTERRUPT           0x010c07
 #define E_ITS_INVALL_UNMAPPED_COLLECTION       0x010d09
diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
index fabcac1..ddd2780 100644
--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -102,6 +102,7 @@ struct its_device {
 
        /* the head for the list of ITTEs */
        struct list_head itt_head;
+       u32 nb_eventid_bits;
        u32 device_id;
 };
 
@@ -180,6 +181,7 @@ static struct its_ite *find_ite(struct vgic_its *its, u32 
device_id,
 #define GIC_LPI_OFFSET 8192
 
 #define VITS_ESZ 8
+#define VITS_TYPER_IDBITS 16
 
 /*
  * Finds and returns a collection in the ITS collection table.
@@ -380,7 +382,7 @@ static unsigned long vgic_mmio_read_its_typer(struct kvm 
*kvm,
         * DevBits low - as least for the time being.
         */
        reg |= 0x0f << GITS_TYPER_DEVBITS_SHIFT;
-       reg |= 0x0f << GITS_TYPER_IDBITS_SHIFT;
+       reg |= (VITS_TYPER_IDBITS - 1) << GITS_TYPER_IDBITS_SHIFT;
        reg |= (VITS_ESZ - 1) << GITS_TYPER_ITT_ENTRY_SIZE_SHIFT;
 
        return extract_bytes(reg, addr & 7, len);
@@ -547,6 +549,7 @@ static u64 its_cmd_mask_field(u64 *its_cmd, int word, int 
shift, int size)
 
 #define its_cmd_get_command(cmd)       its_cmd_mask_field(cmd, 0,  0,  8)
 #define its_cmd_get_deviceid(cmd)      its_cmd_mask_field(cmd, 0, 32, 32)
+#define its_cmd_get_size(cmd)          its_cmd_mask_field(cmd, 1,  0,  5)
 #define its_cmd_get_id(cmd)            its_cmd_mask_field(cmd, 1,  0, 32)
 #define its_cmd_get_physical_id(cmd)   its_cmd_mask_field(cmd, 1, 32, 32)
 #define its_cmd_get_collection(cmd)    its_cmd_mask_field(cmd, 2,  0, 16)
@@ -737,6 +740,9 @@ static int vgic_its_cmd_handle_mapi(struct kvm *kvm, struct 
vgic_its *its,
        if (!device)
                return E_ITS_MAPTI_UNMAPPED_DEVICE;
 
+       if (event_id >= BIT_ULL(device->nb_eventid_bits))
+               return E_ITS_MAPTI_ID_OOR;
+
        if (its_cmd_get_command(its_cmd) == GITS_CMD_MAPTI)
                lpi_nr = its_cmd_get_physical_id(its_cmd);
        else
@@ -817,11 +823,15 @@ static int vgic_its_cmd_handle_mapd(struct kvm *kvm, 
struct vgic_its *its,
 {
        u32 device_id = its_cmd_get_deviceid(its_cmd);
        bool valid = its_cmd_get_validbit(its_cmd);
+       u8 nb_eventid_bits = its_cmd_get_size(its_cmd) + 1;
        struct its_device *device;
 
        if (!vgic_its_check_id(its, its->baser_device_table, device_id))
                return E_ITS_MAPD_DEVICE_OOR;
 
+       if (valid && nb_eventid_bits > VITS_TYPER_IDBITS)
+               return E_ITS_MAPD_ITTSIZE_OOR;
+
        device = find_its_device(its, device_id);
 
        /*
@@ -844,6 +854,8 @@ static int vgic_its_cmd_handle_mapd(struct kvm *kvm, struct 
vgic_its *its,
                return -ENOMEM;
 
        device->device_id = device_id;
+       device->nb_eventid_bits = nb_eventid_bits;
+
        INIT_LIST_HEAD(&device->itt_head);
 
        list_add_tail(&device->dev_list, &its->device_list);
-- 
2.5.5

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